This patent is directed to a spring assembly with a protected attachment site, a vibratory apparatus including a spring assembly with a protected attachment site, and a method for manufacturing a spring assembly with a protected attachment site.
In a two-mass vibratory apparatus, a first mass (or exciter mass) is attached to a second mass (e.g., trough) by one or more reactor springs. Often, these reactor springs are in the form of coil springs having an end loop disposed at either end. A washer is placed over one of the end loops, and a fastener (typically a bolt and nut pair) is disposed through the washer and the end loop to secure the coil spring to the first mass or to the second mass.
While reactor springs are conventionally coated with a corrosion-resistant and/or abrasion-resistant coating on the outer surface of the spring, such coatings can become compromised at the contact areas between the spring, the washer, the fasteners and the machinery. These compromised areas can lead to failure of the spring.
One solution has been to attach the reactor spring to the exciter and the trough, and then apply an additional coating over all of the assembled pieces. This additional coating is difficult and time-consuming to apply, and greatly increases the cost of the springs. In fact, it may not be possible to obtain full coverage of the potentially compromised areas, such that the additional coating does not prevent the failure of the spring at these areas.
It would be advantageous to overcome or substantially ameliorate one or more of the disadvantages of existing springs, or at least to provide a useful alternative.